2000 Ford Windstar mass air flow sensor

had mass air flow sensor change 2-3 months later check engine comes back for same thing started shcool for automotive want to know how to check and repair if systems says low or high input indicated look at wiring diagrams how do I check and repair

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Sunday, April 11th, 2010 AT 7:05 AM

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DAVE H

EXPERT

TEST DC: MASS AIRFLOW SENSOR
NOTE:After each service or repair procedure has been completed, reconnect all components. Clear DTCs and repeat QUICK TEST procedures to ensure all EEC-V systems are working properly and DTCs are no longer present.

Check for broken or loose air outlet tube clamps at throttle body and air cleaner assembly. Check for holes and cracks in air outlet tube. Check for worn gaskets between MAF sensor and air cleaner. Repair as necessary. If no problems are detected, start engine and allow to idle. Check for DTCs. If KOER DTC P0505 is present, go to TEST KE, step 2). On A/T models, if engine stalls or cannot maintain idle speed, go to step 7). If KOER DTC P0505 is not present and engine idles okay, raise engine speed to 1500 RPM for 5 seconds, then return to idle. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. If MAF V PID voltage is less than.23 volt, turn ignition switch to OFF position and go to step 4). If MAF V PID voltage is.23 volt or more, go to next step.
NOTE:DTC P1101 may be caused by low battery or by use of a garage exhaust ventilation system. Ensure vehicle is vented to outside atmosphere before repeating QUICK TEST.

3) KOEO/KOER DTC P1101: MAF Output Voltage
Ensure MAF sensor is connected properly. If MAF sensor is not connected properly, repair as necessary and retest. Start engine and allow it to idle. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. If MAF V PID voltage is.46-2.44 volts, no problem is indicated at this time. Turn ignition switch to OFF position and go to TEST Z. If MAF V PID voltage is not.46-2.44 volts, turn ignition switch to OFF position and go to next step.
4) Check VPWR Voltage To MAF Sensor

Disconnect MAF sensor. Turn ignition switch to ON position. Measure voltage between ground and VPWR terminal at MAF sensor harness connector. See Fig. 32-Fig. 35. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, locate and repair open in VPWR circuit.
5) Check PWR GND Circuit

Measure voltage between positive battery terminal and PWR GND terminal at MAF sensor harness connector. If voltage is more than 10 volts, turn ignition switch to OFF position and go to next step. If voltage is 10 volts or less, locate and repair open in PWR GND circuit.
6) Check Resistance Of VPWR Circuit

Turn ignition switch to OFF position. Leave MAF sensor disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Measure resistance between VPWR terminal at MAF sensor harness connector and power relay (LS) or PCM connector terminal No. 71 (all other models). See Fig. 32-Fig. 40. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in VPWR circuit. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
7) Check MAF Circuit For Short To Ground Or MAF RTN Circuit

Measure resistance between MAF RTN terminal at MAF sensor harness connector and PCM connector terminal A38 (MAF RTN) on LS or terminal No. 36 (MAF RTN) on all other models. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in MAF RTN circuit and reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
NOTE:A break in step numbering sequence occurs at this point. Procedure skips from step 12) to step 16). No test procedures have been omitted.

16) DTC P1100: Check MAF Circuit For Intermittent Voltage To PCM

Start engine and allow it to idle. If idle is not stable, go to TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article and diagnose by symptom. Raise engine speed to 1500 RPM for 5 seconds, then return to idle. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. While observing PID, tap on MAF sensor to simulate road shock. Wiggle sensor connector. If any change in PID voltage occurs, inspect MAF sensor connector. Repair connector as necessary. If connector is okay, replace MAF sensor. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. If no change in PID voltage reading occurs, go to next step.
17) Check MAF Circuit For Intermittent Open Or Short

Turn ignition switch to ON position. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. While observing PID, wiggle small sections of wiring harness starting at MAF sensor working toward PCM. If any change in PID voltage occurs, repair wiring harness as necessary. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. If no change in PID voltage reading occurs, no problem is indicated at this time. Turn ignition switch to OFF position and go to TEST Z.
NOTE:A break in step numbering sequence occurs at this point. Procedure skips from step 17) to step 20). No test procedures have been omitted.

Leave ignition switch in OFF position and MAF sensor disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. On LS, measure voltage between PCM connector terminal A31 (MAF) and terminals No. A24, A25, A26 and A27 (PWR GND). On all other models, measure voltage between PCM connector terminals No. 88 (MAF) and No. 103 (PWR GND). If voltage is less than one volt, go to next step. If voltage is one volt or more, repair MAF circuit short to power.
22) Check MAF Circuit For Short To VREF

Measure resistance between PCM harness connector MAF and VREF terminals. See WIRING DIAGRAMS article. If resistance is more than 10 k/ohms and an idle problem is still present, DO NOT diagnose DTC P0103 at this time. Check MAF sensor operation and compare MAF sensor voltages with MASS AIRFLOW table in SENSOR OPERATING RANGE CHARTS - EXCEPT VILLAGER article. If resistance is more than 10 k/ohms and an idle problem is not present, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE. If resistance is 10 k/ohms or less, repair short between MAF and VREF circuits. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
NOTE:A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 25). No test procedures have been omitted.

NOTE:If vehicle has been driven from a higher to a lower altitude for diagnosing, 3 or 4 heavy accelerations at more than 1/2 throttle must be performed to allow BARO PID to update to current altitude. BARO PID must be within plus or minus 6 Hz (plus or minus 2 in. Hg). See Fig. 41.

DTCs P0171, P0172, P0174 and P0175 indicate a problem when adaptive fuel strategy senses a lean or rich condition beyond the minimum or maximum calibrated limit. DTCs P1130 and P1150 indicate when an HO2S fails to switch due to a circuit or fuel exceeding a calibrated limit. DTCs P1131, P1132, P1151 and P1152 indicate a problem when fuel control system does not detect HEGO switching for a calibrated time. Possible causes for these faults are:
Fuel System

Engine oil overfilled, cam timing, cylinder compression or exhaust leaks before or near HO2S.
NOTE:The BARO PID value measurement is actual barometric pressure for the altitude where vehicle is being tested. Weather conditions (high or low pressure areas) may change local barometric pressure by several in. Of Hg plus or minus 3 Hz. (Plus or minus 1 in. Hg).

Ensure MAF sensor is connected. Start engine and bring to normal operating temperature. Using scan tool, access BARO, LONGFT1, LONGFT2 and MAF V PIDs. Check the following:
Ensure BARO PID is about the same as barometric pressure measurement for location, day and altitude of area. See Fig. 41.
Ensure LONGFT1, LONGFT2 PIDs for all injector banks at idle are not more than minus 12 percent.
Ensure MAF V PID at idle in gear or neutral is not more than 30 percent (no more than 1.1 volt) of normal MAF V listed in appropriate pin voltage/PID value chart in appropriate PIN VOLTAGE/PID VALUE CHARTS article.
If 2 out of the 3 checks are not within specification, go to next step. If 2 out of the 3 checks are within specification and DTCs P0171, P0172, P0174, P0175, P1130, P1131, P1132, P1150, P1151 or P1152 are present, go to TEST H, step 42) for gasoline vehicles, or TEST HA, step 42) for natural gas vehicles. If 2 out of the 3 checks are within specification and no DTCs are present but driveability problem still exists, diagnose by symptom. See SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article.
NOTE:OBD-II requirements call for a fuel system DTC to be set on some vehicles although a driveability problem may not be noticeable, with or without the MAF sensor disconnected. If this should occur and BARO, LONGFT1, LONGFT2 and MAF V PID indicate a MAF sensor problem, replace MAF sensor.